Collective cabinet responsibility will be set aside for the second time in a year, this time over Heathrow. Dr Catherine Haddon says this tactic is highly unusual and something Theresa May could come to regret.

The Prime Minister has told us that her government is going to be about more than just Brexit and that Britain is open for business. If so, finally deciding where to build a new airport runway after decades of prevarication should be one of the Government’s biggest moments. Instead, by suspending collective responsibility over the Cabinet vote on Heathrow, Theresa May has shown how the power dynamics of Brexit could stifle effectiveness for years to come.

Collective responsibility should be about May stamping her authority

Collective responsibility is meant to keep disagreements between ministers behind closed doors. It means that the Government’s final decision is one taken by majority – and Cabinet ministers have to abide by that decision or resign. The scale of leaking and briefing coming from within government at the moment, however, appears very far from the focused and supportive Cabinet we might expect to see rallying behind a new prime minister.

Suspension is highly unusual

This type of agreement to differ within Cabinet does not happen often: previously on tariff reform in 1932 and three times over European membership (1975, 1977 and 2016). But Heathrow is a policy choice that has already caused a huge amount of division, and one that crosses party lines. But ultimately it is simply an infrastructure decision. This makes the suspension of collective cabinet responsibility all the more unusual. During the Coalition, we saw a number of suspensions for the Liberal Democrats. But those were about finding a mechanism to hold a coalition government together. It would say a lot about the current make-up of the Cabinet, and the Conservatives more generally, if they started to use agreements to differ to manage divisions within a single party.

Possible mutiny in the ranks

Heathrow is a decision focused ultimately on the question of national interest – although ministers are clearly bringing their own constituency perspectives to the decision. We know that Boris Johnson and Justine Greening are both vehemently opposed to Heathrow, the former promising to ‘lay down in front of the bulldozers’. They could join a long list of ministers down the ages who have found ways to indicate their own personal view, while stating the agreed policy to be the Government’s position. May is probably suspending collective cabinet responsibility because one or more of her ministers has threatened to resign. Many Prime Ministers have managed tricky Cabinet decisions on the basis of how damaged the Government would be by losing a particular minister. Obviously, to lose Johnson as Foreign Secretary would be a major blow, particularly so early into a new government and given that he was such a figurehead of the Leave campaign.

Setting the (wrong) precedent

If building a runway warrants an agreement to differ, what about all the big decisions to come – both on future infrastructure and other, even more contentious, issues? Will any Prime Minister actually be able to take collective decisions? May’s government faces a range of existing and future policy problems in the context of a small parliamentary majority. These would have been hard enough to manage – even without Brexit in the mix. Collective responsibility and the Heathrow decision could have been an opportunity for May to bind her Cabinet together; instead it may lay the foundations for stronger splits to come.